Brush holder assembly



Sept. 6, 1966 w. DRABIK BRUSH HOLDER ASSEMBLY 3 Sheets-Sheet 1 Filed Deo. 9, 1963 mvENTofL Wal/er Drab/k BY c, E?. W

H/'s Attorney Sept. 6, 1966 W. DRABIK BRUSH HOLDER ASSEMBLY Filedk Deo. 9. 196:5 3 Sheets-Sheet 2 w S3 I`"" xl 'mi l In su o be 01'* e f n a''f v N E' 5s gp l In ha. Z l

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"'H' T d@ N N INVENTOR Wa/fer Drab/'k B @RWM H/'s Attorney Sept. 6, 1966 w. DRABIK 3,271,6@5

BRUSH HOLDER ASSEMBLY Filed Dec. 9, 1965 3 Sheets-Sheet 5 rNvENTon Wa/fer Drab/'k H/'s Attorney 271,605 BRUSH HoLDER ASSEMBLY `Walter Drabk, Downers Grove, Ill., assignor to General This invention relates toa brush holder for dynamoelectric machines and more particularly to a brush holder of a type that utilizes a constant force spring of the type 'having a self-rewinding volute.

One of the objects of this invention is to provide a brush holder that can be formed of a die cast material such as brass that carries a plurality of brush spring assemblies that have constant force springs. v

- Another object of this invention is to provide a brush holder that is capable of carrying a plurality of brushes and to provide an arrangement wherein each brush is individually spring-loaded and where it is a relatively simple matter to change brushes.

y Another object of this invention is to provideva brush holding arrangement wherein a pair of brushes are urged into engagement with a rotating conductor such as a comnutator and wherein the pair of brushes are urged against the rotating conductor by constant force springs carried -by a common support that can be snap-fitted to a brush holder.

A further object of this invention is to provide a brush holding arrangement wherein the brush holder is formed with a plurality of chambers or openings which can recelve brushes and wherein the brushholder is provided with means for receiving a constant force spring assembly that has spring arms that become snap iitt'ed with the brush holder body for easy removal and assembly of the spring assembly to the brush holder,

Stillanother object of this invention is to provide a brushholder which is lighter in weight, requires less parts and requires less machining than heretofore known comparableA brush holders. i

Further objects and advantages of the present invention will beapparent from the following description, reference `being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a top plan view of a brush holder made in accordance with this invention.

FIGURE 2 is a sectional view taken along line 2--2 of FIGURE l.

FIGURE 3 is a sectional view taken along line 3 3 of FIGURE 1.

FIGURE 4 is a perspective view of a constant force spring assembly which is used to urge the brushes of the brush holder shown in FIGURE 1 against the commutator.

Referring now to the drawings, the reference numeral generally designates a brush holder which is formed of a die cast material suc-h as die cast brass. The brush holderj10 has an elongated brush supporting section 12, a bracket section 14 and a section 16. The bracket section 114 is secured to a pair of steel posts 18 which are supported by a support 20. The posts 18 are insulated from the support 20l by insulating material 22. A rubber sleeve 23 tits on each insulator 22. The section 16 of the brush holder is adapted to be connected with a terminal of ahigh current capacity and this terminal is connected with a. heavy copper conductor not illustrated.

The brush receiving section 12 is slightly off-set from the bracket section 14 and has a plurality of openings or chambers 24 for receiving brushes. To be more specic,

yUnited States Patent O1" volute portions 48a and 50a.

l yce the section 12 has tive chambers 24 which are identical in configuration and therefore only one of the chambers will be described in detail.

`Each chamber 24 is dened by inner walls 24a, 24b,

Referring now to FIGURE 4, a brush spring -retainer y assembly is illustrated which is used in the assembly shown in FIGURE 1. This assembly includes a U-shaped part 34 which is formed of a plastic material. The part 34 has four integral lugs 34a two of which are shown in FIGURE 4. The other two lugs are on the opposite side of part 3.4. The legs 36 and 38 of the U-shaped part 34 carry fiat springs 40 and 42 which due to their own resilience, take the position shown in FIGURE 4. The spring 40 has a slot 44 while the spring 42 has a slot 46.

The inner walls of the legs 36 and 38 carry constant v force springs 48 and 50 which each have self-rewinding These springs are wellknown to those skilled in the art and :are capable of applying a constant force to a brush or to ot-her` devices as the length of the device with which they are used shortens. Thus in the case of brushes, the volute portions 48 and 50 wind up as the brushes wear and a constant force is applied to the brushes regardless of the length of the brushes.

The spring 50 and one end of the flat spring 40 are secured to the leg 36 by a rivet 52 shown in FIGURE 3.

In a similar fashion, the spring 48 and the flat spring 42A 'are secured to the leg 38 by a rivet 54.

Referring now more particularly to FIGURE 3, -it is seen that the legs 36 and 38 of the U-shaped member are disposed within the slots 26 and 28 of the brush holder. It is also seen that when the U-shaped part 34 is in place, the projections 32 and 34 fit into t-he openings 44 and 46 formed in the springs 40 and 42.

The constant tension springs 50 and 48 urge the carbon brushes 56 and 58 into engagement with a rotating conductor which may be, for example, a commutator 60 of a dynamo'electric machine which can be a direct current generator. The brushes 56 and 58 are disposed within the chambers 24 and one wall of each brush engages the other wall of the other brush.` The ends 56a and 58a of the brushes are inclined yas shown to ride on the commutator 60. The top ends 58'b and 56b of the brushes are also v port are located outside of the walls 66 and 68 as is clear from FIGURE 3. The brushes 56 and 58 engage the inner walls 24b and 24d of the brush holder.

The top end of each brush is secured to copper conductors, for example, conductors 70 and 72 for the brush 58 and conductors 74 and 76 for the brush 56. The opposite ends of these conductors are secured to a terminal 78 which in turn is secured to the brush holder 10 by a bolt 80. These conductors serve to electrically connect the brushes with the die cast brass portion bolder 10.

The brush spring retainer assembly which is shown in FIGURE 4 can be readily removed from the brush holder 10 when it is desired to change brushes in any or all of the chambers 24 and is readily assembled to the brush holder following the change in brushes. move the brush spring retainer, it is only necessary to grasp the at springs 40 andv 42 with the hand and push them toward each other. When the parts 40 and 42 Patented Sept. 6, 19,66A

Thus to reare pushed 'toward each other, the slots 44 and 46 will vclear the projections 30 and 32 and the brush spring retainer can then beremoved .from the brush holder 10. The brush can then be withdrawn from the chamber 24 'and the bolt 80 loosened so that the brushes can be can engagefa top end of the brush holder to prevent part 34 from lbeing pushedftoo far into chamber 24 when s the part 34 is being assembled to the brush holder 10.

In the finaltassembled position of the brush spring retainer, the lower edges of the slots 44 and 46 are pushed up against the lower edges or projections and 32 by the reactive force of the constant force springs 48 and S0.

It will be appreciated that current is transferred to the die cast brass brush holder 10 by the brushes and by the conductors connecting the brushes and the brush holder. The total current from the commutator 60 is taken by a heavy conductor connected to section 16 as pointed out hereinbe-fore.

While the embodiments of the present invention as herein disclosed, constitute a preferred form, it is to bev understood that other forms might be adopted.

What is claimed is as follows:

1. A brush holding arrangement for a dynamoelectric machine comprising, a brush holder having at least one chamber, at least one brush disposed within said chamber, a springy support located outside of said chamber, a constant force spring having a self-rewinding volute engaging one end of the brush, said constant force spring passing through a slot connecting the exterior and interior of said chamber, a spring arm carried by said support, a slot formed in said arm, and means integral with said brush holder fitting within said slot when said support is assembled to said brush holder.

, 2. A brush holding arrangement for a dynamoelectric machine, a brush holder having at least one chamber, a pair of brushes slidably disposed within said chamber and engaging'each other, a U-shaped support member,

,said U-shaped support member carrying a pair of constant force springs and apair of spring arms, said constant'force springs being located on the inside of said U-shaped member and said spring arms being located on the outside of said U-shaped member, said U-shaped support -being located outside of said chamber with said springs passing through slots formedin said brush holder and engageable with one end of said brushes, said spring.

arms having slots which receive integral projections on said brush holder for locking said U-shaped member in 4` to an inner wall of each leg of the U-shaped v 'stilating material.y f

place when said U-shaped member is assembled to said vbrush holder.

3. The brush holding arrangement according to claim Z'Where the brush holder is formed lof a conductive mate- 4. The brush holding arrangement according to claim l- 2 where the U-shaped member is formed of insulating material and wherein the brush holder is formed of a die cast electrically conductive material.

5. A brush spring retainer adapted to be fitted to a brush holder comprising, a support member having rst and second legs, first and second constant force springs each having a self-rewinding'volute portion attached respectively to one wall of each of said legs, and first and second spring arms attached respectively to another wall of said legs,said arms each having a slot and being capable of being moved toward each other manually.

6. A brush spring support adapted to be secured to a brush holder comprising, a U-shaped member, a constant force` spring having a self-rewinding volute attached 8. The brush spring 'retainer according to` claim 6 where the constant force springs and spring-arms are secured to the legs of the U-shaped member'by a common fastener. v

9. A brush holder arrangement for a dynai'rioelectrick machine comprising, a brush holder formed of die cast electrically conductive material, said brush holder'having a plurality of brush holding chambers, a pair of brushes disposed in each of said chambers, said brushes engaging each other within each chamber, a brush spring support assembly for each pair of brushes, said assembly including a U-shaped member formed of insulating material, a pair of constant force springs carried rby each support assembly and engageable with one end of said brushes for urging said -brushes toward a rotating conductor and a pair of spring arms for each of said supports, each of said spring arms having slots which receive integral projecting portions of said brush holder, and conductor means connecting all of said brusheswith said brush holder.

10. The brush holding arrangement according to claim 9 where the spring arms are disposed on the outside of the U-shaped member and the constant force springs on the inside of the U-shaped member.

11. The brush holding arrangement according to claim 9 where the legs of the spring support are located outside of the brush holding chambers.

12. A brush spring retainer adapted to be fitted to a brushholder comprising, a support member having first and second spaced legs, first and second constant force springs each having a self-rewincling volute portion attached respectively to one wall of each of said legs and positioned such that said constant force springs face each other, and first and second spring arms attached respectively to another wall of said legs, said arms each having means engageable with a brushholder for holding said support member lixed to said brushholder, said arms being capable of being moved toward each other manually to release said support member from a brushholder.

13. A brushholding arrangement for a dynamoelectric machine comprising, a brushholder, a brushholding charnber formed in said brushholder, said brushholding chamber slidably supporting a pair of brushes, a spring supporty member having spaced legs, said spring support member carrying a pair of constant force springs which respectively engage the ends of said brushesfor urging said Ibrushes in a direction to engage a conductor, and first and second spring arms supported respectively by said legs, said arms having means engageable with said brushholder for holding said support member fixed to said brushholder, said spring arms being positioned such that they can be manually moved toward each other to release said support member from said brushholder.

References Cited by the Examiner UNITED STATES PATENTS 2,836,745 5/1958 Gillie 310-246 3,020,430 2/1962 Neuhardt s 310-246 3,158,773 1l/1964 Diehl 310-246 MILTON o. HIRSHFIELD, Primary Examiner. D. F. DUGGAN, Assistant Examiner.

member, a spring arm attached to an outside wall of each leg of 

9. A BRUSH HOLDER ARRANGEMENT FOR A DYNAMOELECTRIC MACHINE COMPRISING, A BRUSH HOLDER FORMED OF DIE CAST ELECTRICALLY CONDUCTIVE MATERIAL, SAID BRUSH HOLDER HAVING A PLURALITY OF BRUSH HOLDING CHAMBERS, A PAIR OF BRUSHES DISPOSED IN EACH OF SAID CHAMBER, A BRUSH BRUSHES ENGAGING EACH OTHER WITHIN EACH CHAMBER, A BRUSH SPRING SUPPORT ASSEMBLY FOR EACH PAIR OF BRUSHES, SAID ASSEMBLY INCLUDING A U-SHAPED MEMBER FORMED OF INSULATING MATERIAL, A PAIR OF CONSTANT FORCE SPRINGS CARRIED BY EACH SUPPORT ASSEMBLY AND ENGAGEABLE WITH ONE END OF SAID BRUSHES FOR URGING SAID BRUSHES TOWARD A ROTATING CONDUCTOR AND A PAIR OF SPRING ARMS FOR EACH OF SAID SUPPORTS, EACH OF SAID SPRING ARMS HAVING SLOTS WHICH RECEIVE INTEGRAL PROJECTING PORTIONS OF SAID BRUSH HOLDER, AND CONDUCTOR MEANS CONNECTING ALL OF SAID BRUSHES WITH SAID BRUSH HOLDER. 